A communication channel is a tool used to disseminate advertising messages to a specific target audience. It is an element integrated into a given media outlet. For example, the newspaper Le Monde is a press outlet. In some countries, certain media outlets may be temporarily excluded from advertising. In France, since the implementation of the decree of August 11, 1987 (Article R. 642-4 of the Penal Code), it is now prohibited to use coins or banknotes as a means of communication, as was sometimes done in the past on their reverse side by unauthorized companies.